Slide 38 of 45
Installing mechanical anchors
- How do Mechanical Anchors work?
- Mechanical anchors attach to the concrete through friction by mechanically expanding or “wedging” against the concrete.
- What is important to remember about mechanical anchors?
- These types of anchors are effective:
- If the concrete is in good shape.
- If the minimum edge distance is maintained.
- The proper diameter hole is essential to allow the anchor to properly engage.
- Normally it is the nominal diameter of the anchor.
- If the hole is drilled too deep, you don’t have to clean the hole – this is because the mechanical anchor works 1 ½’ up from the end of the anchor
- Sometimes the bolt will not engage due to air or powder pockets in the area of the expansion wedge.
- This will be apparent when the bolt will not torque to the required strength.
- When this happens, the bolt should be abandoned and a new bolt should be installed nearby in a new hole.
- Wedge anchors have a required torque to properly set them in concrete.
- For sill plate anchors, the range is generally 50-120 ft-lbs.
- The use of plate washers will help reach the required torque without excessive compression of the sill plate under the washer.
- Watch the wood – do not overtighten and crack the wood
- Follow the manufacturer’s recommendation for the required torque and use a calibrated torque wrench.
- Torque releases after 48 hours even when they are properly set.